.test-page {
	height: 100vh;
	overflow: scroll;
	.top {
		height: 200px;
		background: rebeccapurple;
	}

	.center {
		height: 50px;
		background: red;
		position: sticky;
		top: 0;
	}

	.bottom {
		height: 10000px;
		background: yellow;
	}
}